Electronic phase
This is made in collaboration with Francisco Ramirez. The challenge is: Obtain the longest or strongest output in the form of an LED from a 30 seconds kinetic input.
We have decided to explore a stepper motor and a DC motor. We found that stepper (at the same size) will produce much more energy and therefor we have decided to use it. The testing were made with a drill to maximize the result (video below).
The next simple questions would guid all decisions in this project.
-
How to fully use the energy produced from the motor?
-
what are the right components to use base on what specs, what it the calculation?
-
which muscle in our body will produce us the most energy?
Starting from the last question, we chose to use one of the biggest muscles in the body – the Quadriceps muscle. And that we will do with the help of my bicycle. The plan is to fabricate a device that will hold the rear of the bike above the ground allowing the wheel to rotate freely from pedaling. That will rotate the shaft of our stepper motor. This on its own will be a mechanical mechanism project (will post separately). Taking this energy storing and using it efficiently would be the first phase of the project.
Answering the second question – Since stepper motors produces AC current to fully use the energy produced, a rectifier is needed (actually two). Four diodes connected in a way that all the current passing through is on the positive side. For this project better to use a pre made rectifier.
As for the last question about which components (and as important – how to calculate them) we will need rectifiers, capacitors, resistors and a switch. The capacitors will accumulate and store the energy generated from the stepper and converted to DC through the rectifiers in the 30 seconds input. Only then we shall allow the electricity to flow into the LED using a switch.
The resistors here is needed for 2 reasons. A- Protecting the LED, capacitors and rectifier from getting too much current. B- Resist the drop of current (as seen in the video). Resistors (in series) would cost us in lowering the voltage BUT since our LED only requires 3V and we are producing much more, we can allow that and just explode the slower decrease of current.
Kinetic Challenge process from Oryan Inbar on Vimeo.